diff --git a/processor/src/it/java/com/linecorp/decaton/processor/ArbitraryTopicTypeTest.java b/processor/src/it/java/com/linecorp/decaton/processor/ArbitraryTopicTypeTest.java
index 3626f827..8e98e855 100644
--- a/processor/src/it/java/com/linecorp/decaton/processor/ArbitraryTopicTypeTest.java
+++ b/processor/src/it/java/com/linecorp/decaton/processor/ArbitraryTopicTypeTest.java
@@ -16,23 +16,24 @@
 
 package com.linecorp.decaton.processor;
 
+import java.nio.charset.StandardCharsets;
 import java.time.Duration;
 import java.util.concurrent.CountDownLatch;
 import java.util.function.Consumer;
 
 import org.apache.kafka.clients.producer.Producer;
 import org.apache.kafka.clients.producer.ProducerRecord;
+import org.apache.kafka.common.serialization.ByteArrayDeserializer;
+import org.apache.kafka.common.serialization.ByteArraySerializer;
 import org.apache.kafka.common.serialization.Deserializer;
 import org.apache.kafka.common.serialization.LongDeserializer;
 import org.apache.kafka.common.serialization.LongSerializer;
 import org.apache.kafka.common.serialization.Serializer;
-import org.apache.kafka.common.serialization.StringDeserializer;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.ClassRule;
 import org.junit.Test;
 
-import com.linecorp.decaton.client.kafka.PrintableAsciiStringSerializer;
 import com.linecorp.decaton.processor.runtime.DecatonTask;
 import com.linecorp.decaton.processor.runtime.ProcessorSubscription;
 import com.linecorp.decaton.processor.runtime.ProcessorsBuilder;
@@ -108,13 +109,13 @@ private <K, V> void testRetryWithKeyValue(
     }
 
     @Test(timeout = 30000)
-    public void testPrintableAsciiStringKeyValue() throws Exception {
+    public void testBytesKeyValue() throws Exception {
         testRetryWithKeyValue(
-                new PrintableAsciiStringSerializer(),
-                "abc",
-                new PrintableAsciiStringSerializer(),
-                new StringDeserializer(),
-                "value"
+                new ByteArraySerializer(),
+                "key".getBytes(StandardCharsets.UTF_8),
+                new ByteArraySerializer(),
+                new ByteArrayDeserializer(),
+                "value".getBytes(StandardCharsets.UTF_8)
         );
     }